Occupational asthma (OA) is currently the most frequently reported diagnosis of work-related respiratory disease in developed nations. Healthcare workers (HCWs), a sector representing approximately 7 percent of the U.S. workforce, are among some of the occupational groups at risk of development of OA, with reports of increased occurrence of asthma in nurses, animal handlers, respiratory therapists, physicians, and manufacturers of pharmaceuticals, among others. Relatively few studies have been published with information on formal validation of asthma questionnaires, and validation to date has largely focused on the ability of questionnaire items to predict asthma in populations. In order to use questionnaires to study associations between asthma and occupational and non-occupational exposures, it is also essential that the information obtained on these exposures be reliable and valid. Although several questionnaires exist for the evaluation of asthma in the workplace, very few have undergone formal, in-depth validation. Given the increasing importance of asthma as an occupational disease, there is a clear need for better and more reliable, standardized survey instruments that allow the detection of asthma in different working populations, and its characterization in relation to potential etiologic agents and triggers. We propose to develop, validate and field test a new survey instrument for work-related asthma among HCWs, which permits the assessment of occupational and non-occupational exposures that may result in the development of work-related asthma. This 3-year study will be conducted in two phases. The specific aim of Phase I will be to develop and validate a new survey instrument of work- related asthma, for use in healthcare settings. The questionnaire will be validated by administering it to a convenience sample of 100 HCWs (both with and without asthma), and comparing results to "gold standards" for asthma (methacholine bronchial challenge test) and non-occupational exposures risk factors (RAST IgE-specific antibody panel against common environmental aeroallergens and latex). Occupational exposures will be determined by two separate methods: a) a job-exposure matrix (JEM) previously developed by NIOSH for use in healthcare settings, and modified to focus specifically on asthmagens, and b) self-reported exposures, compared to and supplemented by expert industrial hygienist review. The apriori developed JEM will be validated and updated through a series of workplace visits to area hospitals. The specific aims of Phase 2 will be to: 1) cross-validate and field test the new survey instrument in a population-based sample of four occupational groups (nl400 per group) of HCWs (nurses, physicians, respiratory therapists, and occupational therapists), identified through their respective licensing boards in Texas; 2) estimate and compare the prevalence of work-related asthma among these four occupational groups,3) analyze associations between occupational and non-occupational exposures among HCWs with and without asthma in this nonulation and 4) estimate the occunational burden of asthma in these four occupational groups.